In order to inject fuel into the combustion chambers of an internal combustion engine, it is known to use fuel injectors mounted onto the cylinder heads of the engine and including a needle control unit adapted to control the flow of fuel towards each chamber, so as to obtain the desired rate shaping of fuel injection.
The use of an accumulator, where fuel is stored under pressure, to feed fuel injectors enables to inject fuel into combustion chambers without being dependent on the angle of rotation of a cam shaft.
As mentioned in WO-A-2004/033893, an injector can be fed with fuel under relatively high pressure from an accumulator which is charged by a high pressure pump driven by the engine. This injector includes an amplifier adapted to increase the pressure of the fuel coming from the accumulator and a needle control unit adapted to actuate a needle which delivers fuel to a combustion chamber. The high pressure pump must be implemented on the engine, together with long high pressure lines between this pump and the accumulator. This pump and these long lines are exposed to very high pressure and constitute sources of potential leakage which are not easy to handle. This is a problem for the reliability of the injection system.